For decades, magnons have tantalized physicists with their potential for quantum technologies. These tiny magnetic waves ripple through solid materials like ripples spreading across a pond, and their nanoscale wavelengths mean circuits built from them could, in theory, be as small as a coin. But one fundamental problem has kept them from practical use: they vanish almost as soon as they form — until now.
An international team led by Professor Andrii Chumak at the University of Vienna has achieved a dramatic breakthrough, extending magnon lifetimes by nearly 100 times, from a few hundred nanoseconds to up to 18 microseconds. The findings were published in Science Advances on May 1 and have since been recognized as a transformative step for quantum computing.
Why Magnons Matter
Unlike photons, which travel through empty space or optical fibers, magnons move inside solid magnetic materials. Their wavelengths can shrink to the nanometer scale, meaning magnonic circuits could fit on chips no larger than those in today's smartphones.
Because a magnon is an excitation within a solid, it naturally interacts with other fundamental quasiparticles — phonons and photons — making magnons promising building blocks for hybrid quantum systems and quantum metrology. They could serve as a 'quantum bus,' connecting hundreds of qubits along a single shared pathway, solving one of the most stubborn problems in scalable quantum computing.
The Breakthrough
The research team combined two key strategies. First, they used short-wavelength magnons rather than conventional uniform types, as these are naturally less affected by crystal surface defects. Second, ultra-pure spheres of yttrium iron garnet (YIG) were cooled to just 30 millikelvin — a fraction of a degree above absolute zero — freezing out the thermal processes that normally destroy magnons.
The most significant discovery: the remaining limit on magnon lifetime is not a law of physics, but simply material quality. Three spheres of differing purity were tested, and purer material consistently allowed longer magnon survival. Even the least pure sample exceeded all previous records.
Implications
With lifetimes of 18 microseconds, magnons shift from being lossy, short-lived signals to durable carriers of quantum information — comparable to the superconducting qubits used in leading quantum processors today. The clear path forward — better materials, not new physics — means progress could accelerate rapidly.
"This opens the door to quantum computers potentially no larger than a 1-cent coin," the researchers note, envisioning a future where quantum devices are not room-sized installations but everyday portable technology.
